I posted this in the past about Thresh Q...
""Hmm... whose mind shall we snap" -- Thresh Q is all about the psychological battle.
The spell has an inordinately long and easily detectable windup for such a spell (0.5 sec rather than the standard 0.25 or even 0.15 for some missiles, like Morgana's Dark Binding, Elise's Cocoon, or Zyra's Grasping Roots). It's also quite powerful -- we joke internally that the spell's name, Death Sentence, is pretty spot on. How does this play into the psychological terror that Thresh is supposed to manifest?
1. Obviously, the opponent doesn't get the benefit of seeing that long windup if cast from Fog of War/Brush. Any time Thresh isn't visible, the opponent has to live in a state of abject fear. Fortunately for them, Thresh's soul collection mechanic balances this stress by forcing him to come out periodically to play on fairer terms.
2. Death Sentence brings a subtle, but unique mechanic to the league: Thresh doesn't face the exact position toward which he is casting until the end of the cast. As such, the spell is balanced not around opponent reaction time, but around your ability as the Thresh player to anticipate the direction the opponent will try to move in response to the wind up. In turn, the enemy's counterplay is to vary their movement and win the dodging mind game. Try psyching people out by consciously casting it from an initial facing direction slightly off from where you are actually directing the spell."